Please tell me if there are any rules for writing "o" or "a" in a Russian word. Meaning, if a pronounced word has many "a" how do you know if any of them and which one of them is written as "o"(unstressed o)and which one of them is written as "a" ? Can't remember how a word is written if it contains "a", not sure which "a" is written as "a" and which one is written as "o".

2 Answers 2


Checking o/a with finding the same root based words doesn't work if there is an alternation of vowels in the root.

A Here is the list of alternation vowels roots with o/a inside:

  1. зар – зор
  2. клан – клон
  3. твар – твор
  4. лаг – лож

You have to write what you hear, if it is stressed, and o otherwise.


| загар огарок – [загАр, агАрак]                |
| загорел горелый [загар'Эл, гар'Элый]          |
| кланяться поклон [клАнитса, паклОн]           |
| наклонять склонение [наклан'Ат', склан'Энийэ] |
| тварь творчество [твАр', твОрчиства]          |
| творить растворять [ тварИт', раствар'Ат']    |

Another one list of alternation vowels is:

  1. раст
  2. ращ
  3. рос

Here is the rule:

| А (before СТ, Щ)   -раст- / -ращ-  возраст    [вОзраст]       |
|                                    растить    [растИт']       |
|                                    выращивать [вырАщ'иват']   |
|                                    приращение [пр'иращЕн'ийе] |
| О (in other cases) -рос-           заросли    [зАрасл'и]      |
|                                    вырос      [вЫрас]         |
| ---------------------------------------------------------------
| Exceptions:   росток, ростовщик, Ростов, отрасль, Ростислав   |

B Another confusing case is a connecting vowel between roots. Word can be composed of two different ones. In this case you always have to write о, because there is no connecting vowel а.

Example: самолёт, пароход, тепловоз, красно-зелёный, жёлто-оранжевый (compound colors always are written with dash)

C Also if the word has been borrowed from another language (French, German or English for example) it usually follows transliteration rules.


  • "оппонент" that sounds like [апан'Энт] <–> "opponent".
  • "лотерея" [латэр'Эйа] <–> "lottery"
  • "монитор" [ман'итОр] <–> "monitor"

D Or the unstressed vowels can be presented in a suffixes.

Example: - "воровать" [варавАт']

The root here is 'вор'(rubber), 'ова' is a suffix and 'ть' – ending of the verb infinitive form.

Here you can find some basic suffixes in Russian. They are written as they are without modification.

E Furthermore o/a can exist within prefixes. There are about 70 prefixes in Russian language. Some of them change during some rules. You can check them here.


  • подобрать [падабрАт'] (to pick up) Here the prefix is подо- (пада doesn't exist), -бр- is the root, -ать is the infinitive verb ending

  • разослать [разаслАт'] (to send out)


Well, this is a problem of a vowel reduction: unstressed Russian "О" is usually replaced by "А" in the spoken language (called Áканье). So to write it properly one usually has to find a word of the same root with a stressed vowel, so it becomes clear what the root of the word appears to be.

E.g.: "Грозá" (thunderstorm) is pronounced "гразá" only because of reduction, but should be written with "О" as in the plural form where "O" is stressed - "Грóзы" (thunderstorms).

There are exceptions though. After all, the orthography is what the pupils learn in the school for the years.

  • 1
    This works well for native speakers, but probably not so well for those learning Russian.
    – Dima
    Commented Nov 4, 2015 at 15:50
  • @Dima Probably. But I don't know a better way.
    – Matt
    Commented Nov 4, 2015 at 16:16
  • At least using the plural form is a tool, that seems to work. I'm new to the russian language. Does this trick work more often than it doesn't? I mean: Are almost all plural words built this way (switching stressed vowels) ?
    – itmuckel
    Commented Jul 3, 2016 at 8:46
  • 1
    @Micha90 It is true that in many plurals the last syllable is unstressed. So if you have some typical feminine noun ending with stressed "а" then its plural has a stress on the last but one syllable, e.g.: "ногá" - "нóги". But it doesn't work, for example, for masculine nouns ending with consonants, e.g.: "барáн" - "барáны". As you see, here the stress still "switches" from the last syllable to the last but one, and yet it stays on the same vowel.
    – Matt
    Commented Jul 3, 2016 at 13:01

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